Calcium hardness question: to add or not

[CFlaPool]

My mother-in-laws pool has the numbers below. Plaster pool, 18,000 gallons, resurfaced 6-9 months ago, uses liquid chlorine. CSI is good, but I fear CH is too low. Would you raise the CH to 350? Here is link to poolmath pool. PoolMath Logs

 

[Newdude]

With copious amounts of rain I would raise it above 350 as it will forever be dropping.

*providing your fill water is low CH.

 

[CFlaPool]

With copious amounts of rain I would raise it above 350 as it will forever be dropping.

*providing your fill water is low CH.

Yes, our city water is not hard at all. Her pool has a plugged main drain due to leaks, and her El Dorado pool cleaner is always in the skimmer. Are there any issues getting the calcium to dissolve properly?

 

[Newdude]

Are there any issues getting the calcium to dissolve properly?

Nope. Broadcast it and brush. Run the cleaner after just because.

 

[CFlaPool]

Nope. Broadcast it and brush. Run the cleaner after just because.

Thanks. 20lb added. It dissolved quickly with a little brushing. I’ll retest Friday.

 

[CFlaPool]

Thanks. 20lb added. It dissolved quickly with a little brushing. I’ll retest Friday.

Tested today. 250. So it must have been 175 last week. It went up 75 with 20lbs. She has been adding soft city water due to no rain, so that could be why CH did not increase as much as expected. Also, I think the pool may be more like 17000 instead of 15000. I’ll put in another 20# bag of calcium this week.